"A corruption of 'through bass' (in English) in the sense of one which is continuous, hence an approximate translation of Basso continuo. As such, it specifically relates to a characteristic feature of the new style of composition which emerged ca. 1600 replacing the intermittent bass lines of earlier music. The thorough-bass part was usually supplemented with figures, hence the common expression "Figured bass" by which it is also known, indicating the accompanying harmonies which were filled out or "realised" on a keyboard instrument (or lute) in extempore fashion ... together with additional support from other bass (wind and/or string) instruments" (IAML) (Thorin)